Heterogeneous reactions of nitrogen dioxide (NO2) on soils collected from Dalian (S1) and Changsha (S2) were investigated over the relative humidity (RH) range of 5%-80% and temperature range of 278-328 K using a horizontal coated-wall flow tube. The initial uptake coefficients of NO2 on S2 exhibited a decreasing trend from (10 +/- 1.3) x 10(-8) to (3.1 +/- 0.5) x 10(-8) with the relative humidity increasing from 5% to 80%. In the temperature effect studies, the initial uptake coefficients of S1 and S2 decreased from (10 +/- 1.2) x 10(-8) to (3.8 +/- 0.5) x 10(-8) and from (16 +/- 2.2) x 10(-8) to (3.8 +/- 0.4) x 10(-8) when temperature increased from 278 to 288 K for S1 and from 278 to 308 K for S2, respectively. As the temperature continued to increase, the initial uptake coefficients of S1 and S2 returned to (7.9 +/- 1.1) x 10(-8) and (20 +/- 3.1) x 10(-8) at 313 and 328 K, respectively. This study shows that relative humidity could influence the uptake kinetics of NO2 on soil and temperature would impact the heterogeneous chemistry of NO2.